I am with you, I don't like them My friend had one and bith her dentist and the GP got on to her about it- she ruined her teeth playing with it all the time and GP told her the piercing was to blame for her recurring throat infections.

You will have to talk to her again (without nagging) and really try to get across how much you dislike them but at the same time it was her decision to have it done and keep it and you can't expect her to change. You may have to come up with a comprimse to the situation, or hope the novelty wears off soon and she takes it out permanently.

I am not personally a fan of tongue piercings BUT I have to say that it's a personal thing, a piercing, a tattoo, a hair style or whatever. It's good you can be honest with her but ultimately I think it's one of those situations of HER BODY HER CHOICE.
I absolute detest when my hubby shaves his head and moan at him big style, but when he feels like it he still does it. Just like he prefers my hair blonde, but I've still had it coloured really dark coz it's for me not him. We both have tattoos but even though we may ask each others opinions before we get new ones, we don't ask for each others approvals. I think you'll have to get used to it. Is it more important to you than she is?

Sometimes you don't like things, but you have to live with them, I don't like tattoo's or piercing', Frank is literally covered in tattoo's, I can't stand them, but I know trying to stop him will just end up with an argument and him getting another tattoo anyway. The more you moan, the more stubborn and determined they become.